What is the approach to the medical evaluation of galactorrhea?

Medical Evaluation of Galactorrhea

The medical evaluation of galactorrhea should include measurement of serum prolactin level as the initial diagnostic test, followed by assessment of thyroid and renal function, pregnancy testing in women of reproductive age, and brain MRI if hyperprolactinemia is confirmed without other identifiable causes. 1, 2

Initial Assessment

History

• Medication review: Focus on drugs that can elevate prolactin (antipsychotics, antidepressants, opioids, metoclopramide, domperidone) 3, 4
• Reproductive history: Menstrual irregularities, fertility concerns, recent pregnancy/breastfeeding 5
• Associated symptoms: Headaches, visual changes (suggesting pituitary mass), fatigue, cold intolerance (suggesting hypothyroidism) 1
• Nipple stimulation, chest wall irritation, or recent breast trauma 6
• Stress levels and sexual activity (can transiently increase prolactin) 6

Physical Examination

• Breast examination: Confirm true galactorrhea (milky discharge) vs other nipple discharge
• Visual field testing: To detect deficits suggesting pituitary macroadenoma
• Thyroid examination: Assess for enlargement, nodules, or tenderness 5
• Signs of androgen excess: Hirsutism may suggest polycystic ovary syndrome 5

Diagnostic Testing Algorithm

1. First-line laboratory tests:

   • Serum prolactin level
   • Pregnancy test (for women of reproductive age)
   • Thyroid-stimulating hormone (TSH)
   • Renal function tests (BUN, creatinine) 2

2. If prolactin is elevated:

   • Review and discontinue medications that may cause hyperprolactinemia
   • Repeat prolactin measurement if medication was discontinued
   • If persistently elevated without medication cause, proceed to imaging 1

3. Imaging studies:

   • MRI of the brain with focus on pituitary and hypothalamus for patients with:
     • Persistent unexplained hyperprolactinemia
     • Normal prolactin but concerning neurological symptoms
     • Significantly elevated prolactin levels (>100 ng/mL, suggesting prolactinoma) 3, 2

4. Additional testing based on clinical suspicion:

   • Follicle-stimulating hormone/luteinizing hormone levels if amenorrhea present
   • Dynamic thyroid function tests if subclinical hypothyroidism suspected 4

Management Based on Etiology

Medication-Induced Galactorrhea

• Discontinue or replace the offending medication when possible 2
• Consider alternative medications within the same class with lower potential for hyperprolactinemia 1

Prolactinoma

• Microadenomas (<10 mm):

  • Dopamine agonist therapy is first-line treatment
  • Cabergoline is preferred due to better efficacy and tolerability (5-10 times more potent than bromocriptine) 2
  • Bromocriptine is preferred for women planning pregnancy 3

• Macroadenomas (≥10 mm):

  • More aggressive treatment with dopamine agonists
  • Surgical resection if medical therapy fails or visual field defects persist 1

Hypothyroidism

• Thyroid hormone replacement therapy 4

Idiopathic Galactorrhea with Normal Prolactin

• Reassurance if not bothersome
• Short course of low-dose dopamine agonist if bothersome 1

Special Considerations

Pregnancy

• Close monitoring of women with known prolactinomas during pregnancy due to risk of tumor enlargement 6
• Discontinue cabergoline one month before attempting conception 3

Normoprolactinemic Galactorrhea

• Not all cases of galactorrhea are associated with elevated prolactin 4
• Consider subclinical hypothyroidism or medication effects even with normal prolactin 4

Treatment Pitfalls to Avoid

• Failing to check prolactin levels in patients with galactorrhea
• Not considering medication effects as a common cause
• Overlooking hypothyroidism as a potential cause even with normal TSH
• Neglecting to obtain brain imaging when hyperprolactinemia remains unexplained
• Treating asymptomatic patients with normal prolactin levels unnecessarily

Bromocriptine and cabergoline can cause significant side effects including nausea, dizziness, and hypotension. Start at low doses and titrate gradually to minimize these effects 7.